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    The MongoDB\Driver\Cursor class

    (mongodb >=1.0.0)

    소개

    The MongoDB\Driver\Cursor class encapsulates the results of a MongoDB command or query and may be returned by MongoDB\Driver\Manager::executeCommand() or MongoDB\Driver\Manager::executeQuery(), respectively.

    클래스 개요

    MongoDB\Driver\Cursor implements Traversable {
    /* 메소드 */
    final private __construct ( void )
    final public MongoDB\Driver\CursorId getId ( void )
    final public MongoDB\Driver\Server getServer ( void )
    final public bool isDead ( void )
    final public void setTypeMap ( array $typemap )
    final public array toArray ( void )
    }

    Table of Contents

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    User Contributed Notes 5 notes

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    14
    max-p at max-p dot me
    8 years ago
    As one might notice, this class does not implement a hasNext() or next() method as opposed to the now deprecated Mongo driver.

    If, for any reason, you need to pull data from the cursor procedurally or otherwise need to override the behavior of foreach while iterating on the cursor, the SPL \IteratorIterator class can be used. When doing so, it is important to rewind the iterator before using it, otherwise you won't get any data back.

    <?php
    $cursor     = $collection->find();
    $it = new \IteratorIterator($cursor);
    $it->rewind(); // Very important

    while($doc = $it->current()) {
            var_dump($doc);
            $it->next();
    }
    ?>

    I used this trick to build a backward compatibility wrapper emulating the old Mongo driver in order to upgrade an older codebase.
    up
    5
    tdrpic
    8 years ago
    If you find that it would be easier to use arrays (instead of objects) for the returned documents, add the following after executing your query:

    $cursor->setTypeMap(['root' => 'array', 'document' => 'array', 'array' => 'array']);
    up
    5
    peichi40233 at gmail dot com
    7 years ago
    There used to be a count() method in the old mongo extension (http://docs.php.net/manual/en/mongocursor.count.php), however, this feature seems to be deleted in mongodb.

    I've seen some people use executeCommand() to do that, but I found it much more earier to just use the toArray() method and count the returned array.

    For example:
    $manager = new MongoDB\Driver\Manager();
    $query = new MongoDB\Driver\Query($filter, $options);
    $cursor = $manager->executeQuery('db.collection', $query)->toArray();
    var_dump(count($cursor));
    up
    3
    mikemartin2016 at gmail dot com
    8 years ago
    I noticed that  ->sort is missing from the cursor.  Seems like the old driver has more functionality.

    [red.: The way how cursors are created is different between the drivers. In the old driver, the cursor would not be created until after the first rewind() call on the iterator.

    In the new driver the cursor already exists. Because sort (and limit and skip) parameters need to be send to the server, they can not be called after the cursor already has been created.

    You can use sort (and limit and skip) with the new driver as well, by specifying them as options to the Query as shown in this example: http://php.net/manual/en/mongodb-driver-query.construct.php#refsect1-mongodb-driver-query.construct-examples]
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    0
    cg at papoo dot de
    3 years ago
    Since php-mongodb version 1.9.0 Cursor implements Iterator, but if you need to support older versions too, you can conditionally wrap the cursor with IteratorIterator:

    <?php
    $iterator     = $collection->find();

    if (!(    $iterator implements Iterator)) {
          $iterator = new \IteratorIterator($iterator);
    }
    ?>
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